<template>
  <section class="todoapp">
    <header class="header">
      <h1>todos</h1>
      <input
        v-model="newTodo"
        class="new-todo"
        autofocus
        autocomplete="off"
        placeholder="What needs to be done?"
        @keydown.enter="addTodo"
      />
    </header>
    <section v-show="todos.length" class="main">
      <input id="toggle-all" v-model="allDone" class="toggle-all" type="checkbox" />
      <label for="toggle-all">Mark all as complete</label>
      <ul class="todo-list">
        <li
          v-for="(item, i) in filterTodos"
          :key="item.id"
          class="todo"
          :class="{ editing: item === editingItem, completed: item.completed }"
        >
          <div class="view">
            <input v-model="item.completed" class="toggle" type="checkbox" />
            <label @dblclick="editingTodo(item)">{{ item.title }}</label>
            <button class="destroy" @click="removeTodo(i)"></button>
          </div>
          <input
            v-model="item.title"
            v-todo-focus="item === editingItem"
            class="edit"
            type="text"
            @keydown.enter="editTodo"
            @blur="editTodo"
            @keydown.esc="cancelEditTodo(item)"
          />
        </li>
      </ul>
    </section>
    <footer v-show="todos.length" class="footer">
      <span class="todo-count">{{ remaining }} item left</span>
      <ul class="filters">
        <li><a :class="{ selected: visibility == 'all' }" @click="visibility = 'all'">All</a></li>
        <li>
          <a :class="{ selected: visibility == 'active' }" @click="visibility = 'active'">Active</a>
        </li>
        <li>
          <a :class="{ selected: visibility == 'completed' }" @click="visibility = 'completed'">
            Completed
          </a>
        </li>
      </ul>
      <button v-show="todos.length > remaining" class="clear-completed" @click="todos = []">
        Clear completed
      </button>
    </footer>
  </section>
</template>

<script>
import { getList } from '@/api/todolist'
import { reactive, watch, computed, toRefs, onMounted } from '@vue/composition-api'
const filters = {
  all(todos) {
    return todos
  },
  active(todos) {
    return todos.filter((todo) => {
      return !todo.completed
    })
  },
  completed(todos) {
    return todos.filter((todo) => {
      return todo.completed
    })
  }
}
export default {
  name: 'Vue3',
  directives: {
    'todo-focus'(el, binding) {
      if (binding.value) {
        el.focus()
      }
    }
  },
  setup() {
    /* todo app 开始 */
    const state = reactive({
      newTodo: '',
      todos: [],
      editingItem: null,
      visibility: 'all'
    })
    let cachedTitle = ''
    const filterTodos = computed(() => {
      return filters[state.visibility](state.todos)
    })
    const remaining = computed(() => {
      return filters.active(state.todos).length
    })
    const allDone = computed({
      get() {
        return remaining.value === 0
      },
      set(value) {
        state.todos.forEach((todo) => {
          todo.completed = value
        })
      }
    })
    watch(
      () => state.todos,
      () => {
        console.log('changed')
      },
      {
        deep: true
      }
    )
    onMounted(async () => {
      state.todos = await getList()
    })
    function addTodo(e) {
      if (!state.newTodo.trim()) {
        return
      }
      state.todos.push({
        id: new Date().getTime(),
        title: state.newTodo,
        completed: false
      })
      state.newTodo = ''
      e.target.blur()
    }
    function editingTodo(item) {
      cachedTitle = item.title
      state.editingItem = item
    }
    function editTodo(e) {
      e.target.blur()
      cachedTitle = ''
      state.editingItem = null
    }
    function removeTodo(i) {
      state.todos.splice(i, 1)
    }
    function cancelEditTodo(item) {
      item.title = cachedTitle
      state.editingItem = null
    }
    /* todo app 结束 */

    return {
      ...toRefs(state),
      filterTodos,
      remaining,
      allDone,
      addTodo,
      editingTodo,
      editTodo,
      removeTodo,
      cancelEditTodo
    }
  }
}
</script>

<style scoped>
.todoapp {
  position: relative;
  margin: 200px auto;
  width: 550px;
  background: #fff;
  box-shadow: 0 2px 4px 0 rgb(0 0 0 / 20%), 0 25px 50px 0 rgb(0 0 0 / 10%);
}
.todoapp input::-webkit-input-placeholder {
  font-style: italic;
  font-weight: 300;
  color: #e6e6e6;
}

.todoapp input::-moz-placeholder {
  font-style: italic;
  font-weight: 300;
  color: #e6e6e6;
}

.todoapp input::input-placeholder {
  font-style: italic;
  font-weight: 300;
  color: #e6e6e6;
}

.todoapp h1 {
  position: absolute;
  top: -155px;
  width: 100%;
  font-size: 100px;
  font-weight: bold;
  text-align: center;
  color: rgba(70, 235, 20, 0.15);
  -webkit-text-rendering: optimizeLegibility;
  -moz-text-rendering: optimizeLegibility;
  text-rendering: optimizeLegibility;
}

.new-todo,
.edit {
  position: relative;
  margin: 0;
  width: 100%;
  font-size: 24px;
  font-family: inherit;
  font-weight: inherit;
  line-height: 1.4em;
  border: 0;
  color: inherit;
  padding: 6px;
  border: 1px solid #999;
  box-shadow: inset 0 -1px 5px 0 rgba(0, 0, 0, 0.2);
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.new-todo {
  padding: 16px 16px 16px 60px;
  border: none;
  background: rgba(0, 0, 0, 0.003);
  box-shadow: inset 0 -2px 1px rgba(0, 0, 0, 0.03);
}

.main {
  position: relative;
  z-index: 2;
  border-top: 1px solid #e6e6e6;
}

.toggle-all {
  text-align: center;
  border: none; /* Mobile Safari */
  opacity: 0;
  position: absolute;
}

.toggle-all + label {
  width: 60px;
  height: 34px;
  font-size: 0;
  position: absolute;
  top: -52px;
  left: -13px;
  -webkit-transform: rotate(90deg);
  transform: rotate(90deg);
}

.toggle-all + label:before {
  content: '❯';
  font-size: 22px;
  color: #e6e6e6;
  padding: 10px 27px 10px 27px;
}

.toggle-all:checked + label:before {
  color: #737373;
}

.todo-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.todo-list li {
  position: relative;
  font-size: 24px;
  border-bottom: 1px solid #ededed;
}

.todo-list li:last-child {
  border-bottom: none;
}

.todo-list li.editing {
  border-bottom: none;
  padding: 0;
}

.todo-list li.editing .edit {
  display: block;
  width: 506px;
  padding: 12px 16px;
  margin: 0 0 0 43px;
}

.todo-list li.editing .view {
  display: none;
}

.todo-list li .toggle {
  text-align: center;
  width: 40px;
  /* auto, since non-WebKit browsers doesn't support input styling */
  height: auto;
  position: absolute;
  top: 0;
  bottom: 0;
  margin: auto 0;
  border: none; /* Mobile Safari */
  -webkit-appearance: none;
  appearance: none;
}

.todo-list li .toggle {
  opacity: 0;
}

.todo-list li .toggle + label {
  /*
Firefox requires `#` to be escaped - https://bugzilla.mozilla.org/show_bug.cgi?id=922433
IE and Edge requires *everything* to be escaped to render, so we do that instead of just the `#` - https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/7157459/
*/
  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23ededed%22%20stroke-width%3D%223%22/%3E%3C/svg%3E');
  background-repeat: no-repeat;
  background-position: center left;
}

.todo-list li .toggle:checked + label {
  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23bddad5%22%20stroke-width%3D%223%22/%3E%3Cpath%20fill%3D%22%235dc2af%22%20d%3D%22M72%2025L42%2071%2027%2056l-4%204%2020%2020%2034-52z%22/%3E%3C/svg%3E');
}

.todo-list li label {
  word-break: break-all;
  padding: 15px 15px 15px 60px;
  display: block;
  line-height: 1.2;
  transition: color 0.4s;
}

.todo-list li.completed label {
  color: #d9d9d9;
  text-decoration: line-through;
}

.todo-list li .destroy {
  display: none;
  position: absolute;
  top: 0;
  right: 10px;
  bottom: 0;
  width: 40px;
  height: 40px;
  margin: auto 0;
  font-size: 30px;
  color: #cc9a9a;
  margin-bottom: 11px;
  transition: color 0.2s ease-out;
  border: none;
}

.todo-list li .destroy:hover {
  color: #af5b5e;
}

.todo-list li .destroy:after {
  content: '×';
}

.todo-list li:hover .destroy {
  display: block;
}

.todo-list li .edit {
  display: none;
}

.todo-list li.editing:last-child {
  margin-bottom: -1px;
}

.footer {
  color: #777;
  height: 40px;
  padding: 0 15px;
  font-size: 13px;
  text-align: center;
  border-top: 1px solid #e6e6e6;
  line-height: 40px;
}

.footer:before {
  content: '';
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 50px;
  overflow: hidden;
  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2), 0 8px 0 -3px #f6f6f6, 0 9px 1px -3px rgba(0, 0, 0, 0.2),
    0 16px 0 -6px #f6f6f6, 0 17px 2px -6px rgba(0, 0, 0, 0.2);
}

.todo-count {
  float: left;
  text-align: left;
}

.todo-count strong {
  font-weight: 300;
}

.filters {
  margin: 0;
  padding: 0;
  list-style: none;
  position: absolute;
  right: 0;
  left: 0;
}

.filters li {
  display: inline;
}

.filters li a {
  color: inherit;
  margin: 3px;
  padding: 3px 7px;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 3px;
}

.filters li a:hover {
  border-color: rgba(175, 47, 47, 0.1);
}

.filters li a.selected {
  border-color: rgba(175, 47, 47, 0.2);
}

.clear-completed,
html .clear-completed:active {
  float: right;
  position: relative;
  line-height: 40px;
  text-decoration: none;
  cursor: pointer;
  border: none;
}

.clear-completed:hover {
  text-decoration: underline;
}

.info {
  margin: 65px auto 0;
  color: #bfbfbf;
  font-size: 10px;
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
  text-align: center;
}

.info p {
  line-height: 1;
}

.info a {
  color: inherit;
  text-decoration: none;
  font-weight: 400;
}

.info a:hover {
  text-decoration: underline;
}

/*
Hack to remove background from Mobile Safari.
Can't use it globally since it destroys checkboxes in Firefox
*/
@media screen and (-webkit-min-device-pixel-ratio: 0) {
  .toggle-all,
  .todo-list li .toggle {
    background: none;
  }

  .todo-list li .toggle {
    height: 40px;
  }
}

@media (max-width: 430px) {
  .footer {
    height: 50px;
  }

  .filters {
    bottom: 10px;
  }
}
</style>
